Question

Calculate the number of gram atoms in 4.6 grams of sodium (Na = 23)

Answer 1

Given:
Weight of the sodium = 4.6g
Mass of sodium atom = 23
Number of gram moles of Na = `"Mass of Sodium"/"Mass of sodium atom"`
= `4.6/23` = 0.2g
Molar mass of CuSO₄.5H₂O = ( 64 ) + ( 32 ) + (9 x 16) + (10 x 1) = 250
Molar mass of 5.H₂O molecules = ( 10 x 1) + ( 5 x 16) = 90
Percentage of water of Crystallisation = `[ 90 xx 100]/250` = 36%